1. Field of Disclosure
The present disclosure relates to a display panel. More particularly, the present disclosure relates to a display panel with pixel drivers.
2. Description of Related Art
With the vigorous development of display technology, flat panel displays have been widely applied in daily life. In the flat panel displays, active Matrix Organic Light-Emitting Diode (AMOLED) display is very popular for its performances of high image quality, high contrast, and high reaction speed.
FIG. 1 is a schematic diagram of a conventional pixel-driving circuit. Power voltages OVDD and OVSS are applied to a pixel-driving circuit 10 for providing a driving current passing through the pixel-driving circuit 10. A scan signal SCAN is utilized to drive the pixel-driving circuit 10 according to a data voltage Data. The pixel-driving circuit 10 is a conventional structure with only two transistors and only one capacitor (known as 2T1C structure). To be more specific, a gate terminal of one transistor is directly connected with the scan line (marked as SCAN in FIG. 1) and a drain terminal of one transistor is directly connected with the data line (marked as Data in FIG. 1). On the other hand, a gate terminal of the other transistor is directly connected with the source terminal of the first transistor and an electrical terminal of the capacitor. A drain terminal of the other transistor is directly connected with the power line (marked as OVDD in FIG. 1) and the other electrical terminal of the capacitor. A source terminal of the other transistor is directly connected with an electrical terminal of the LED. The other electrical terminal of the LED is directly connected with the ground wire (marked as OVSS in FIG. 1). However, the operational characteristics of different pixels within the same panel will not be identical due to the variations in manufacturing process. Therefore, when identical data voltages Data are provided to the pixels, driving currents of different pixels may still be inconsistent, and it causes non-uniform brightness on the AMOLED display panel. In addition, voltage drop characteristics (known as IR drop) related to different pixels can be inconsistent. The inconsistent voltage drops of different pixels cause the non-uniform brightness on different areas over the AMOLED display panel as well as impact the image quality.
In order to solve aforesaid problems, such as the non-uniform brightness on the display panel induced by the inconsistent threshold voltages of the driving transistors of the pixels, a conventional driving circuit requires individual control circuits (including scan-driving circuits and timing controllers) for generating individual scan signals, individual light-emitting signals and individual resetting signals, which are suitable for those driving transistors with inconsistent threshold voltages. In the conventional solution, individual shift registers, buffers, power sources and clock signal wirings are required to generate those signals, such that large layout space will be occupied by these additional components and it is against a goal to narrow down a frame-width on a display panel.
Therefore, it is one of the most important topics to balance the brightness of pixels over the display panel and reduce the area required for the entire circuit layout.